I've compared stencil printing adhesive versus acquiring a dispensing equipment. Had breakdown all the costs against each other. It end up that Stencil Printing Adhesive is more costly than equipment dispensing machine in the long term (5 years). But i'm expecting one good question from our management regarding the Extra Labour Cost on Cleaning the stencil (which needs to be frequent to avoid aperture clogging on 0805's and 0603's).

I have assumed a full working period of 5 years without holidays or day off at a regular/basic rate. Also calculated at twice the hourly rate of operator since the operator should be doing other things at the time of cleaning the stencil.

This is the question that I'm expecting:

"In Reality there's no additional cost or extra cost for the cleaning time since there is no increase on operator's wage in doing the cleaning but instead just an additional load or job for the operators at the same wage cost."

How will I re-BUT that question or comment specially if there's not much impact on productivity as I believe that they are considered as hidden impact on productivity and quality.

Quite simply, when the stencil is being auto cleaned, the operator can be doing another element of work. Also as mentioned, the stencil will be thoroughly cleaned as opposed to having any human errors leading to blocked or damaged stencils.

The time/money saved should be MANUAL CLEAN TIME x NUMBER OF STENCILS x HOURLY RATE over whatever period.

During justifications, most people (me included) tend to do the sums up to the allotted payback period. But in reality, unless your "item" coincidentally packs in at that very time, the item will carry on saving you money beyond that point.

"In Reality there's no additional cost or extra cost for the cleaning time since there is no increase on operator's wage in doing the cleaning but instead just an additional load or job for the operators at the same wage cost."

I'd have to agree....cleaning time would be a weak justification...IF I were a manger, I'd shoot it down...the cleaning time isn't part of the manufacturing process of the board and would NOT be accounted into the total LABOR cost when costing your products (boy do I sound like a bean counter!!!).....cleaning stencils is basically something that can be done "off-line" while your automatic stencil printer is running.

Also, as Bill says below, a good stencil cleaner that can do a good job of cleaning adhesives would drastically cut down the time - although for MOST cleaners out on the market, substantial "pre-cleaning" still has to be done (ie you can take a stencil with GLOBS of paste or glue and throw it into the cleaner), so no matter what, there'll still be some labour involved.

What�s wrong with your printing process and what improvement do you expect from dispensing ? I can imagine that it�s more convinient just to have this process inline, no worrying about stencils, cleaning, changing printer setting, just replacing a cartridge now and than. But is it that simple, is the dispensing process so much more desireable ? Have you calculated the time you need for each PCB and do you have made an estimation of your first part yield ? Thought is was the other way round, changing from dispensing to printing.

Not sure if I agree with your justification but I might need to read it a few more times to figure it out. I agree that aquiring a dispensing machine is is a good purchase. Maybe you should let him in on the material savings. How many adhesive stencils due you have in-house; how many will you buy in the next month, year; Is it cheaper to pay the person spitting out the program or the person designing the stencil? When it comes down to which is better, who cares; they both get the job done, But the dispenser is more flexible to process issues that may arise.( high profile parts, wave fixture problems, ECN's, Deviations, etc...) Some times a flat out cost difference doesn't show the whole picture.

I feel Woldgang poses an interesting question. It seems you have already decided that dispensing is the path you wish to take. Yet can you tell us why? Is there a flexibility vs. throughput arguement here?

Justification of dispense via the cleaning process may be difficult. But keep in mind the additional cleaning chemical costs per unit produced (especially if your cleaner does not have filtration on the tanks thus requiring more frequent change over) Another issue will be the additional waste water disposal which depending on your local regulations can significantly add up. An evaporator can counteract this yet it does nothing to lower the cleaning chemical consumption rate.

These additional costs may factor in as some of the "Hidden Costs" in addition to labor costs for the time taken for frequent chemical changeout in tanks (once every 2-3 weeks for unfiltered, once every 2-3 months filtered depending on epoxy type)

Using manual cleaning labor costs to justify a dispenser may pose a challenge compared to justification of an automated cleaner unless you need the dispenser's flexibility. The cleaner will eventually pay for itself but like any capital equipment purchase the ture goal is to get that return on investment as soon as possible.

Will a better cleaning process coupled with your screenprinter's throughput get a better ROI than a dispenser? I'm sure only your production criteria will tell.

Cleaning time SHOULD be accounted for into labor costs when costing product because although it CAN be done off-line, you still need to clean the contaminated screen and this has to be done by a worker who is (hopefully) charging for this (remedial) service. Unfortunately this is always overseen by management and unless spotted you will lose the arguement.(and look stupid and small and not worthy etc...etc)